Improvement in hair-spring-testing apparatus for watches



V J. LOG:A`N. Wa-tobSpring Tester. No. 105,467. .Patented July 19, ,1870.

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IJ'oH ,LO GAN, or BOSTON, MAssAcHUs-E'r'rs,

Letters Patent N0. 105,467, dated uly 19, 1870.

IMPRovs ENr iN HaIR-sPRING-TEsTING APPARATUS. ron WATcHns.

Thescheduh referredfio in^theae Letters Patent and making part of the sam'e 'o all whom it mag/'concern Be it knownthat LJ'OHN LOGAN, of Boston, in the I County ofjsulfolk and State of Massachusetts, have invented Apparatus `.for Ascertaiuing the Length of Hair-springs; and I-do hereby declare th'at'the following, when taken in connection with the drawing which accompanies and forms apart oi'. this specification, is a description -ot' my invention sufficient to enable those i skilled 'in the art to practiceit.

In watch-making, much time has to be expended in the ad ustment of the hair-springs, ,the length of which determmesthe duration of 'the oscillations of the balance-wheel.

. Heretofore, the length of hair-springs has been determined by actual trial of them in ;the Watches of which theyform .a part, which is a tedious, and, therefore, expensive operation, great care having to'he exerc1sed,'an d there being. no* special conveniences* or apphances in Watches for confining the spring at 'considerably varying lengths, or forreadily entering to or .takmg fi'om its place a balance-wheel withits attached 'hair-spring. i a V My invention consists .in anapparatus provided with meansfor readily introducing 'a balance-wheel and its' attachedhair-spring to a time=keeping train, actnated by a mainspring,`and for readily rempving the same therefrom, and with,. means for clamplng the free end of the hair-spring at any reasonable distance along its length; also, in such an apparatus,combining with the imainspring a supplemental spring, so that, by adjust- ,:ment of the latter, an additional impelling'foree-can be .brought readily to act upon the hairespringto be adjusled,`and so that said fcrce can be as :readily removed; and also in the arrangement with g said train and the index which shows its rate of movement, of another reg'nla'ted time-keeping train hariugan index, so that, bycorhparingztlw rate of movement of'the train having the hair-spring, the length of which is to be adjusted, with the rate of. movement'o'fthe regulated train, the operator can see at a glance whether s the hair-spring to be adjusted as to length has its free end so clampedthat the op'erative part of the spring is too 'long, too short, or' just right.

` Figure 1 bf the drawing showsmy apparat'us partly inlside elevation and partly in vertical` section, and

Figure 2 shows thesame 'in plan. V In this apparat us'there isnothing' novel about the time-keeping trains, per se; any pair; of good similar e ;trains may be used, in each of which the power` efa ,mainspr'ing is brought to "ain eseapement, operative "upon a balanc`4wheel provided with a' hair-spring;

therefore, in this description, reference` to the general and well-known construction and operation of such train's will be omitted.

Two' suitable springdmpelled time-keeping traius are arranged in one frame common to both, 'that on the left of fig. 2 being provided with regulated balance-wheel and hair-spring, s"o as to move at the standardTrate, and carryingan index-hand, a.

Theright-hand side of the appuratus is .arranged for testing the hair-springs to be: adjusted as to length, this bein'gthe most convenient for the operator.-

' The balance-wheel bridge b of the right-hand train is removably fixed'in' position by two steady pins, c c, and theswinging spring clamp d, so that the bridge b can be easily removed to. enter abalance-wheel and to *remove it. V

in which is the upper; pivot-bearing` for the balancewheel, and in the frame, in line with said scre'w, is anothersimilar serew, e', so that, by adjustment of both or either of said screws, the balanceqvheel may be. properly set. p

., On the left of the bridge b is ,arranged a clampiug I Said apparatus consists of a cam'or eccentric', which can be tuineda by lever g, so asto clamp the hair spring between said cam and a projection from the `piece h, which holds the cam. I

When a balance is placed in position between the'. Screws c and e', theleveng is so placed as to leave an opening between its cam and the projection from piece 'h, a'ndathe 'free end of 'the-hair-spring is introduced into said opening. The said end is left exceeding the maximum length required, and-is drawn between the decin' necessary, and, `by movement of lever g, is clamped the're.- V

The right-hand train is then'allowed to vibrate' the.

i movement of theindex-hand i with reference to the' index-hand .a, both moving in the same direction, s0 that it 'is' easily-seen',-if they move isochrononsly, or whether hand t, gains or loses-with reference to hand a. If the former, then the free end of 'the spring f is unclamped, and is drawn back and again clamped, and the 'rate of movement" observed. If the lat-.ter, the spring is unclamped, its free end drawn further through beyond the cam,` and again clamped, and the rate of movement observed.

experimental train a supplemental spring, j, fixed to the arbor la of the mainspr'ing;

The end of spring j' is formed as a hook, and pinsl Said bridge is provided with an adjnstable screw, c,

apparatns, suited to receive the free end of the hair spring f.

'said cam and projeetion 'as far asthe operatormay balance-wheel,and, the ;operator observes the rate of As the. degree of stress of the mains pring operates tainerease or diminish the degree of vibration-of the v balance-wheel, I have added to the mainspring of the are set around 'spring j, in the frame of the apparatus,

so that, by the aid of a knob, m, fixed on spring m', it 'can be coiled' to any desired degree of tension required, and retained at such tension by coupling the hook upon any one of the pins l, as may be desired.

When, after suitable adjustments of the hair-spring f, and Observations of the rate of movement indicated by the index hand 'i, under light and strong stress ex-` erted from the main spring and its supplement, the inovements of both trains are found to be practically isochronous; then the operator breaks off the end of the hair-springprojecting beyond the point where it is clamped, which brings the length of the spring such that it is ready to be placed in the watch to which it belongs, when no further adjustment as to length will be needed, except that which is within the range of the movement o'f the regulator, with which the watch is provided.

If desired, a minute-hand, n, may be added to the regulated train, so that the rate of gain or loss ,of i, with reference to a, may be observed conveniently for .any number 'of minutes.

The operator, on commencing his observation of comparison, can 1'eaclily, with any small instrument, check or accelerate the movement of one of the hands a or 2' so that, ata given moment, they will start from corresponding positions, and then the gain or loss of movement of the' hand i over the' hand a will be re'adily seen.

l`he indicating-hands a and i, I place on the fifthwheel arbors, which wheels are the escapement-wheels,

so that each movement of the said hands indicates one-fifth of a second, instead of placing the indicatinghands on the arbors of the fourth-wheels, .where they would, by each movement, indicate seconds;-a.nd thus :I am enabled'more quickly and readily todetect any 'Variation in the rate of movement of the two indicat ing-hands.

-I claim An apparatus' for determining the proper length of hair-springs for Watches, the same consisting of two independent time-keeping spring-driven trains, one of which is adjusted 'to-'run at the standard rate, and the.

other of which has provision for easily and temporarily connecting with it balance-wheels with attached hairsprings, the lengths of which are to be determined, the two trains' having each rapidly-moving indicating hands designed to move isochronously, and exposed, so that they may be turned and set to the same start-4 ing point.

Also, in combination with the main driving-spring 

